Abstract
A cloud-resolving model is used to study the effects of a vertical temperature dipole on convective cloud development. Such dipole anomalies, with a warm-above-cool structure in the troposphere, are known to be forced by mesoscale convective systems (MCSs) in the Tropics. The experiments involve letting convection develop in perturbed initial soundings with open lateral boundary conditions. Convection is driven solely by surface fluxes. In the control run, a field of deep convection ensues. With a strong dipole anomaly that is warm in the upper troposphere, no clouds ascend beyond the middle troposphere. In this case, cumulus congestus clouds strongly moisten the midtroposphere with relative humidity increases by up to 24% by the end of the 6-h simulation. With a half-strength anomaly, a mixed population results: mainly middle-topped congestus clouds, but with some intermittent deep cells. The partitioning between cloud types is somewhat sensitive to model resolution, with a change from 1- to 0.5-km grid spacing resulting in relatively more congestus clouds and fewer deep cells.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2092-2100 |
| Number of pages | 9 |
| Journal | Journal of the Atmospheric Sciences |
| Volume | 61 |
| Issue number | 16 |
| DOIs | |
| State | Published - Aug 15 2004 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Atmospheric Science
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Effect of vertical dipole temperature anomalies on convection in a cloud model. / Bister, Marja; Mapes, Brian E.
In: Journal of the Atmospheric Sciences, Vol. 61, No. 16, 15.08.2004, p. 2092-2100.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of vertical dipole temperature anomalies on convection in a cloud model
AU - Bister, Marja
AU - Mapes, Brian E
PY - 2004/8/15
Y1 - 2004/8/15
N2 - A cloud-resolving model is used to study the effects of a vertical temperature dipole on convective cloud development. Such dipole anomalies, with a warm-above-cool structure in the troposphere, are known to be forced by mesoscale convective systems (MCSs) in the Tropics. The experiments involve letting convection develop in perturbed initial soundings with open lateral boundary conditions. Convection is driven solely by surface fluxes. In the control run, a field of deep convection ensues. With a strong dipole anomaly that is warm in the upper troposphere, no clouds ascend beyond the middle troposphere. In this case, cumulus congestus clouds strongly moisten the midtroposphere with relative humidity increases by up to 24% by the end of the 6-h simulation. With a half-strength anomaly, a mixed population results: mainly middle-topped congestus clouds, but with some intermittent deep cells. The partitioning between cloud types is somewhat sensitive to model resolution, with a change from 1- to 0.5-km grid spacing resulting in relatively more congestus clouds and fewer deep cells.
AB - A cloud-resolving model is used to study the effects of a vertical temperature dipole on convective cloud development. Such dipole anomalies, with a warm-above-cool structure in the troposphere, are known to be forced by mesoscale convective systems (MCSs) in the Tropics. The experiments involve letting convection develop in perturbed initial soundings with open lateral boundary conditions. Convection is driven solely by surface fluxes. In the control run, a field of deep convection ensues. With a strong dipole anomaly that is warm in the upper troposphere, no clouds ascend beyond the middle troposphere. In this case, cumulus congestus clouds strongly moisten the midtroposphere with relative humidity increases by up to 24% by the end of the 6-h simulation. With a half-strength anomaly, a mixed population results: mainly middle-topped congestus clouds, but with some intermittent deep cells. The partitioning between cloud types is somewhat sensitive to model resolution, with a change from 1- to 0.5-km grid spacing resulting in relatively more congestus clouds and fewer deep cells.
UR - http://www.scopus.com/inward/record.url?scp=4444337626&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4444337626&partnerID=8YFLogxK
U2 - 10.1175/1520-0469(2004)061<2092:EOVDTA>2.0.CO;2
DO - 10.1175/1520-0469(2004)061<2092:EOVDTA>2.0.CO;2
M3 - Article
AN - SCOPUS:4444337626
VL - 61
SP - 2092
EP - 2100
JO - Journals of the Atmospheric Sciences
JF - Journals of the Atmospheric Sciences
SN - 0022-4928
IS - 16
ER -